-- todo allow config passed in
local log = require"navigator.util".log
local trace = require"navigator.util".trace
local uv = vim.loop
_NG_Loading = false

_LoadedClients = {}
local loader = nil
packer_plugins = packer_plugins or nil -- suppress warnings

-- packer only

local highlight = require "navigator.lspclient.highlight"

local has_lsp, lspconfig = pcall(require, "lspconfig")
if not has_lsp then
  return {
    setup = function()
      print("loading lsp config failed LSP may not working correctly")
    end
  }
end

local util = lspconfig.util
local config = require"navigator".config_values()

-- local cap = vim.lsp.protocol.make_client_capabilities()
local on_attach = require("navigator.lspclient.attach").on_attach
-- gopls["ui.completion.usePlaceholders"] = true

-- lua setup
local library = {}

local path = vim.split(package.path, ";")

table.insert(path, "lua/?.lua")
table.insert(path, "lua/?/init.lua")

local function add(lib)
  for _, p in pairs(vim.fn.expand(lib, false, true)) do
    p = vim.loop.fs_realpath(p)
    if p then
      library[p] = true
    end
  end
end

-- add runtime
add("$VIMRUNTIME")

-- add your config
-- local home = vim.fn.expand("$HOME")
add(vim.fn.stdpath('config'))

-- add plugins it may be very slow to add all in path
-- if vim.fn.isdirectory(home .. "/.config/share/nvim/site/pack/packer") then
--   add(home .. "/.local/share/nvim/site/pack/packer/opt/*")
--   add(home .. "/.local/share/nvim/site/pack/packer/start/*")
-- end

library[vim.fn.expand("$VIMRUNTIME/lua")] = true
library[vim.fn.expand("$VIMRUNTIME/lua/vim")] = true
library[vim.fn.expand("$VIMRUNTIME/lua/vim/lsp")] = true
-- [vim.fn.expand("~/repos/nvim/lua")] = true

-- TODO remove onece PR #944 merged to lspconfig
local path_sep = require"navigator.util".path_sep()
local strip_dir_pat = path_sep .. "([^" .. path_sep .. "]+)$"
local strip_sep_pat = path_sep .. "$"
local dirname = function(path)
  if not path or #path == 0 then
    return
  end
  local result = path:gsub(strip_sep_pat, ""):gsub(strip_dir_pat, "")
  if #result == 0 then
    return "/"
  end
  return result
end
-- TODO end

local setups = {
  gopls = {
    on_attach = on_attach,
    -- capabilities = cap,
    filetypes = {"go", "gomod"},
    message_level = vim.lsp.protocol.MessageType.Error,
    cmd = {
      "gopls", -- share the gopls instance if there is one already
      "-remote=auto", --[[ debug options ]] --
      -- "-logfile=auto",
      -- "-debug=:0",
      "-remote.debug=:0"
      -- "-rpc.trace",
    },

    flags = {allow_incremental_sync = true, debounce_text_changes = 500},
    settings = {
      gopls = {
        -- more settings: https://github.com/golang/tools/blob/master/gopls/doc/settings.md
        -- flags = {allow_incremental_sync = true, debounce_text_changes = 500},
        -- not supported
        analyses = {unusedparams = true, unreachable = false},
        codelenses = {
          generate = true, -- show the `go generate` lens.
          gc_details = true --  // Show a code lens toggling the display of gc's choices.
        },
        usePlaceholders = true,
        completeUnimported = true,
        staticcheck = true,
        matcher = "fuzzy",
        diagnosticsDelay = "500ms",
        experimentalWatchedFileDelay = "100ms",
        symbolMatcher = "fuzzy",
        gofumpt = false, -- true, -- turn on for new repos, gofmpt is good but also create code turmoils
        buildFlags = {"-tags", "integration"}
        -- buildFlags = {"-tags", "functional"}
      }
    },
    root_dir = function(fname)
      return util.root_pattern("go.mod", ".git")(fname) or dirname(fname) -- util.path.dirname(fname)
    end
  },
  clangd = {
    flags = {allow_incremental_sync = true, debounce_text_changes = 500},
    cmd = {
      "clangd", "--background-index", "--suggest-missing-includes", "--clang-tidy",
      "--header-insertion=iwyu"
    },
    filetypes = {"c", "cpp", "objc", "objcpp"},
    on_attach = function(client)
      client.resolved_capabilities.document_formatting = true
      on_attach(client)
    end
  },
  rust_analyzer = {
    root_dir = function(fname)
      return util.root_pattern("Cargo.toml", "rust-project.json", ".git")(fname)
                 or util.path.dirname(fname)
    end,
    filetypes = {"rust"},
    message_level = vim.lsp.protocol.MessageType.error,
    on_attach = on_attach,
    settings = {
      ["rust-analyzer"] = {
        assist = {importMergeBehavior = "last", importPrefix = "by_self"},
        cargo = {loadOutDirsFromCheck = true},
        procMacro = {enable = true}
      }
    },
    flags = {allow_incremental_sync = true, debounce_text_changes = 500}
  },
  sqls = {
    filetypes = {"sql"},
    on_attach = function(client, bufnr)
      client.resolved_capabilities.execute_command = true
      highlight.diagnositc_config_sign()
      require"sqls".setup {picker = "telescope"} -- or default
    end,
    flags = {allow_incremental_sync = true, debounce_text_changes = 500},
    settings = {
      cmd = {"sqls", "-config", "$HOME/.config/sqls/config.yml"}
      -- alterantively:
      -- connections = {
      --   {
      --     driver = 'postgresql',
      --     datasourcename = 'host=127.0.0.1 port=5432 user=postgres password=password dbname=user_db sslmode=disable',
      --   },
      -- },
    }
  },
  sumneko_lua = {
    cmd = {"lua-language-server"},
    filetypes = {"lua"},
    on_attach = on_attach,
    flags = {allow_incremental_sync = true, debounce_text_changes = 500},
    settings = {
      Lua = {
        runtime = {
          -- Tell the language server which version of Lua you're using (most likely LuaJIT in the case of Neovim)
          version = "LuaJIT",
          -- Setup your lua path
          path = vim.split(package.path, ";")
        },
        diagnostics = {
          enable = true,
          -- Get the language server to recognize the `vim` global
          globals = {"vim", "describe", "it", "before_each", "after_each", "teardown", "pending"}
        },
        completion = {callSnippet = "Both"},
        workspace = {
          -- Make the server aware of Neovim runtime files
          library = library,
          maxPreload = 2000,
          preloadFileSize = 40000
        },
        telemetry = {enable = false}
      }
    },
    on_new_config = function(cfg, root)
      local libs = vim.tbl_deep_extend('force', {}, library)
      libs[root] = nil
      cfg.settings.Lua.workspace.library = libs
      return cfg
    end
  },
  pyright = {
    on_attach = on_attach,
    cmd = {"pyright-langserver", "--stdio"},
    filetypes = {"python"},
    flags = {allow_incremental_sync = true, debounce_text_changes = 500},
    settings = {
      python = {
        analysis = {
          autoSearchPaths = true,
          useLibraryCodeForTypes = true,
          diagnosticMode = "workspace"
        }
      }
    }
  },
  ccls = {
    on_attach = on_attach,
    init_options = {
      compilationDatabaseDirectory = "build",
      root_dir = [[ util.root_pattern("compile_commands.json", "compile_flags.txt", "CMakeLists.txt", "Makefile", ".git") or util.path.dirname ]],
      index = {threads = 2},
      clang = {excludeArgs = {"-frounding-math"}}
    },
    flags = {allow_incremental_sync = true}
  }
}

local servers = {
  "angularls", "gopls", "tsserver", "flow", "bashls", "dockerls", "julials", "pylsp", "pyright",
  "jedi_language_server", "jdtls", "sumneko_lua", "vimls", "html", "jsonls", "solargraph", "cssls",
  "yamlls", "clangd", "ccls", "sqls", "denols", "graphql", "dartls", "dotls",
  "kotlin_language_server", "nimls", "intelephense", "vuels", "phpactor", "omnisharp",
  "r_language_server", "rust_analyzer", "terraformls"
}

if _NgConfigValues.lspinstall == true then
  local has_lspinst, lspinst = pcall(require, "lspinstall")
  if has_lspinst then
    local srvs = lspinst.installed_servers()
    log('lspinstalled servers', srvs)
    if #srvs > 0 then
      servers = srvs
    end
  end
end

local default_cfg = {
  on_attach = on_attach,
  flags = {allow_incremental_sync = true, debounce_text_changes = 500}
}

-- check and load based on file type
local function load_cfg(ft, client, cfg, loaded)
  if lspconfig[client] == nil then
    log("not supported by nvim", client)
    return
  end

  local lspft = lspconfig[client].document_config.default_config.filetypes
  local cmd = cfg.cmd

  local should_load = false
  if lspft ~= nil and #lspft > 0 then
    for _, value in ipairs(lspft) do
      if ft == value then
        should_load = true
      end
    end
    if should_load == false then
      return
    end

    trace('lsp for client', client, cfg)
    if cmd == nil or #cmd == 0 or vim.fn.executable(cmd[1]) == 0 then
      log('lsp not installed for client', client, cmd)
      return
    end

    for _, c in pairs(loaded) do
      if client == c then
        -- loaded
        trace(client, "already been loaded for", ft, loaded)
        return
      end
    end

    if lspconfig[client] == nil then
      error("client " .. client .. " not supported")
      return
    end

    lspconfig[client].setup(cfg)
    -- dont know why but 1st lsp client setup may fail.. could be a upstream defect
    lspconfig[client].setup(cfg)
    log(client, "loading for", ft)
  end
  -- need to verify the lsp server is up
end

local function wait_lsp_startup(ft, retry, user_lsp_opts)
  retry = retry or false
  local clients = vim.lsp.get_active_clients() or {}
  local loaded = {}
  local capabilities = vim.lsp.protocol.make_client_capabilities()
  capabilities.textDocument.completion.completionItem.snippetSupport = true

  for _, client in ipairs(clients) do
    if client ~= nil then
      table.insert(loaded, client.name)
    end
  end
  for _, lspclient in ipairs(servers) do
    if user_lsp_opts[lspclient] ~= nil and user_lsp_opts[lspclient].filetypes ~= nil then
      if not vim.tbl_contains(user_lsp_opts[lspclient].filetypes, ft) then
        trace("ft", ft, "disabled for", lspclient)
        goto continue
      end
    end

    if vim.tbl_contains(_NgConfigValues.lsp.disable_lsp or {}, lspclient) then
      log("disable lsp", lspconfig)
      goto continue
    end

    local default_config = {}
    if lspconfig[lspclient] == nil then
      print("lspclient", lspclient, "no longer support by lspconfig, please submit an issue")
      goto continue
    end
    if lspconfig[lspclient].document_config and lspconfig[lspclient].document_config.default_config then
      default_config = lspconfig[lspclient].document_config.default_config
    else
      print("missing document config for client: ", lspclient)
      goto continue
    end

    default_config = vim.tbl_deep_extend("force", default_config, default_cfg)

    local cfg = setups[lspclient] or {}
    cfg = vim.tbl_deep_extend("keep", cfg, default_config)
    if not vim.tbl_contains(cfg.filetypes, ft) then
      trace("ft", ft, "disabled for", lspclient)
      goto continue
    end

    -- if user provides override values
    cfg.capabilities = capabilities
    if user_lsp_opts[lspclient] ~= nil then
      -- log(lsp_opts[lspclient], cfg)
      local disable_fmt = false

      log(lspclient, _NgConfigValues.lsp.disable_format_ft)
      if vim.tbl_contains(_NgConfigValues.lsp.disable_format_ft or {}, lspclient) then
        log("fileformat disabled for ", lspclient)
        disable_fmt = true
      end
      cfg = vim.tbl_deep_extend("force", cfg, user_lsp_opts[lspclient])
      if _NgConfigValues.combined_attach == nil then
        cfg.on_attach = function(client, bufnr)
          on_attach(client, bufnr)
          if disable_fmt then
            client.resolved_capabilities.document_formatting = false
          end
        end
      end
      if _NgConfigValues.combined_attach == "mine" then
        if _NgConfigValues.on_attach == nil then
          error("on attach not provided")
        end
        cfg.on_attach = function(client, bufnr)
          _NgConfigValues.on_attach(client, bufnr)
          if disable_fmt then
            client.resolved_capabilities.document_formatting = false
          end
        end
      end
      if _NgConfigValues.combined_attach == "both" then
        cfg.on_attach = function(client, bufnr)
          if _NgConfigValues.on_attach then
            _NgConfigValues.on_attach(client, bufnr)
          end
          if setups[lspclient] and setups[lspclient].on_attach then
            setups[lspclient].on_attach(client, bufnr)
          else
            on_attach(client, bufnr)
          end
          if disable_fmt then
            client.resolved_capabilities.document_formatting = false
          end
        end
      end
    end

    load_cfg(ft, lspclient, cfg, loaded)
    ::continue::
  end

  local efm_cfg = user_lsp_opts['efm']
  if efm_cfg then
    lspconfig.efm.setup(efm_cfg)
  end
  if not retry or ft == nil then
    return
  end
  --
  local timer = vim.loop.new_timer()
  local i = 0
  timer:start(1000, 200, function()
    clients = vim.lsp.get_active_clients() or {}
    i = i + 1
    if i > 5 or #clients > 0 then
      timer:close() -- Always close handles to avoid leaks.
      log("active", #clients, i)
      _NG_Loading = false
      return true
    end
    -- giveup
    -- _NG_Loading = false
  end)
end

local function setup(user_opts)
  local ft = vim.bo.filetype
  if _LoadedClients[ft] then
    log("navigator is loaded for ft", ft)
    return
  end
  if user_opts ~= nil then
    log("navigator setup", user_opts)
  end
  trace(debug.traceback())
  user_opts = user_opts or _NgConfigValues -- incase setup was triggered from autocmd

  if _NG_Loading == true then
    return
  end
  if ft == nil then
    ft = vim.api.nvim_buf_get_option(0, "filetype")
  end

  if ft == nil or ft == "" then
    log("nil filetype")
    return
  end
  local retry = true
  local disable_ft = {
    "NvimTree", "guihua", "clap_input", "clap_spinner", "vista", "vista_kind", "TelescopePrompt",
    "csv", "txt", "markdown", "defx"
  }
  for i = 1, #disable_ft do
    if ft == disable_ft[i] or _LoadedClients[ft] then
      trace("navigator disabled for ft or it is loaded", ft)
      return
    end
  end

  local bufnr = vim.fn.bufnr()
  local uri = vim.uri_from_bufnr(bufnr)

  if uri == 'file://' or uri == 'file:///' then
    log("skip loading for ft ", ft, uri)
    return
  end

  trace('setup', user_opts)
  log("loading for ft ", ft, uri)
  highlight.diagnositc_config_sign()
  highlight.add_highlight()
  local lsp_opts = user_opts.lsp

  _NG_Loading = true

  if vim.bo.filetype == 'lua' then
    local slua = lsp_opts.sumneko_lua
    if slua and not slua.cmd then
      if slua.sumneko_root_path and slua.sumneko_binary then
        lsp_opts.sumneko_lua.cmd = {
          slua.sumneko_binary, "-E", slua.sumneko_root_path .. "/main.lua"
        }
      else
        lsp_opts.sumneko_lua.cmd = {"lua-language-server"}
      end
    end
  end

  wait_lsp_startup(ft, retry, lsp_opts)

  _LoadedClients[ft] = true
  -- _LoadedClients[ft] = vim.tbl_extend("keep", _LoadedClients[ft] or {}, {ft})

  _NG_Loading = false

  -- if not _NgConfigValues.loaded then
  --   vim.cmd([[autocmd FileType * lua require'navigator.lspclient.clients'.setup()]]) -- BufWinEnter BufNewFile,BufRead ?
  --   _NgConfigValues.loaded = true
  -- end
end
return {setup = setup}